Retractable supports and actuating means therefor



Nov. 8, 1955 J P. MCBRIDE 2,723,173

RETRACTABLE SUPPORTS AND ACTUATING INVENTOR ATTORNEY Nov. 8, 1955 J. P. M BRIDE 2,723,173

RETRACTABLE SUPPORTS AND ACTUATING MEANS THEREFOR Filed Jan. 15, 1954 2 Sheets-Sheet 2 j 45 44 ATTORNEY United States Patent RETRACTABLE SUPPORTS AND ACTUATING MEANS THEREFOR James Peter McBride, New York, N. Y., assignor to Gerald S. Carrick, Pleasautville, N. Y.

Application January 15, 1954, Serial No. 404,302

5 Claims. Cl. 311-85) This invention relates to supports and more particularly to retractable and extendable supporting means for a tray or other supporting surface together with actuating means for such extendable and retractable supports which actuating means serves to lock the supports in either extended or retracted position. v

Heretofore, many types of extendable and retractable supports, such as legs, have been provided and these have taken the form of individualy hinged legs which may be locked in extended or retracted position and also, there have been instances where such legs have been linked together for simultaneous operation. There has also, been provided actuating means for such legs or supports and this actuating means has taken many forms but in the main, has been objectionable from the standpoint of presenting many wear points which result in considerable lost motion and in certain instances, such lost motion results in failure to completely extend or retract the legs or other supports.

Another objectionable feature of the prior art devices has been the locking means which has been utilized to secure the legs or other supports in extended or retracted position since in many instances, such locking means has been extremely difiicult to release and where the same has been of such design that convenient release may be obtained, the same has often failed and permitted collapse of the legs or other supports when in extended position. Furthermore, the prior art structures have, in the main, been of relatively fragile and flimsy construction resulting in frequent failures of the parts and also such structures have failed to provide a firm and steady base which will support a tray, table or other relatively heavy supporting surface ,upon which various articles may be placed.

It is therefore an object of this invention to provide extendable and retractable supporting means'fora supporting surface, such as a tray, table or the like, which supporting means may be conveniently extended or re tracted by operation of a simple actuating member.

A further object of the invention is the provision of extendable and retractable supporting means for a tray, table or the like, which may be extended or retracted by operation of a single actuating means,.which actuating means also serves to release a locking mechanism which securely holds the supporting means in extended or retracted position.

A still further object of the invention is v.the provision of extendable and retractable supporting means which may take the form of individual legs or pairs of legs and in which the same may be simultaneously extended or retracted by'operation of a single'actuating means.

Another object of the invention is the provision of extendable and retractable supporting means for a tray, table or the like, which may be extended or retracted by operation of a single actuating means and in which the locking means for holding the supporting means in extended or retracted position forms a part of the operat- 2,723,173 Patented Nov. 8, 1955 ing mechanism and is released in either the extended or retracted position by operation of the same single actuating means.

A further object of the invention is the provision of extendable or retractable supporting means for trays, tables or the like, in which the number of moving parts or wear points is maintained at a minimum.

A still further object of the invention is the provision of retractable and extendable supporting means for trays, tables or the like, in which all of the parts may be conveniently and economically constructed by well known metal working operations, such as die-stamping and assembled by relatively unskilled labor thereby maintaining the cost of construction at a minimum.

Another object of the invention is the provision of extendable and retractable supporting means for trays,

- tables and the like, which is of relatively rugged construction thereby providing a firm support for the same and in which the operating means for extending and retracting the supporting means is of such construction that bending or other distortion, occurring in the normal use of the device will in no way impair the operation thereof.

Further objects and advantages of the invention will become apparent from the following description taken in conjunction with the accompanying drawing wherein:

Fig. l is a view in perspective showing by way of illustration, a tray equipped with the extendable and retractable supporting means and operating means therefor constructed in accordance with this invention;

Fig. 2, a fragmentary bottom plan view showing the operating means for the extendable and retractable supporting means in the two positions occupied when the supporting means is extended or retracted;

Fig. 3, a fragmentary side elevational view showing a portion of the operating mechanism for extending and retracting the supporting means of this invention and with the supporting means in extended position;

Fig. 4, a fragmentary sectional view on the line 44 of Fig. 3; i

Fig. 5, a fragmentary sectional view on the line 55 of Fig. 2 and showing the locking means in locked position for maintaining the supporting means in one terminal position;

Fig. 6, a fragmentarry side elevational view similar to Fig. 3, and showing the operating means for the extendable and retractable supporting means in various positions occupied during operation of the device;

Fig. 7, a fragmentary sectional view on the line 7-7 of Fig. 6;

Fig. 8, a fragmentary sectional view on the line 8-8 of Fig. 7, and showing the operating mechanism. in released position and just prior to movement of the supporting means toward the opposite extreme position;

Fig. 9, a fragmentary sectional view similar to Fig. 8 and showing the operating mechanism in an intermediate position;

Fig. 10, a fragmentaryside elevational view similar to Fig. 3 and showing the supporting means in retracted position and the position occupied by the operating means at such time; and

Fig. 11, a fragmentary sectional view showing the operating means in locked position when the extendable and retractable supporting means is in retracted position.

With continued reference to the drawing the mechanism of this invention is shown as applied to a tray 10,

but it is to be understood that this is for purposes of illustration only, since the extendable and retractable supporting means could as well be applied to a table or other supporting surface which required substantially rigid supporting means, but which, at certain times must be stored in confined places in which case, retraction of the supporting means is highly desirable. The illustration of the mechanism of this invention on a tray is not therefore, to be considered in any way a limitation. The supporting means of this invention may well comprise spaced legs 11 and 12, leg 11 being provided with arms 13 and 14 connected by a portion 15, the central part of which is offset as at 16 to provide spaced floor or other surface engaging portions 17 and 18. The spaced arms 13 and 14 are connected by a shaft 19 which in turn is rotatably mounted in angle brackets 20 and 21 secured to the tray 16 by spot welding or any other suitable means. The shaft 19 is provided with a lever arm 22 fixed thereto, the purpose of which will be presently described.

The leg 12 is also provided with spaced arms 23 and 24 connected by a portion 25, the central part 26 of which is offset to provide spaced floor or other surface engaging portions 27 and 28. The spaced arms 23 and 24 of leg 12 are connected adjacent their ends by a shaft 29 which in turn is pivotally mounted on angle brackets 30 and 31 secured to the tray 10 by spot-welding or any other suitable means. The shaft 29 is provided with a lever arm 32 fixed thereto, the purpose of which will be presently described.

Secured to the under side of tray 10 by spot-welding or any other suitable means is a cheek piece 33 and pivotally mounted on cheek piece 33 by a rivet 34 or any other suitable means is an operating arm 35. A link 36 is pivotally connected at 37 to one end of arm and the opposite end of link 36 is pivotally connected at 38 to the lever 32 secured to the shaft 29. A second link 39 is pivotally secured at 40 to the arm 35 at a point equidistant from the pivot point 34 as the pivotal connection 37 of link 36. The opposite end of link 39 is pivotally connected at 41 to the lever arm 22 secured to the shaft 19. It will therefore be seen that oscillation of the arm 35 about the pivot point 34 will serve to oscillate the shafts 19 and 29 and at the same time, move legs 11 and 12 to extended position, as shown in Fig. 1, or to retracted position with the legs 11 and 12 folded against the lower surface of the tray 10.

The arm 35 is provided with an elongated offset portion 42 which terminates in a downwardly extending portion 43 extending at substantially right angles to the offset portion 42. A latch strip 44 is secured to the lower surface of tray 10 by spot-welding or any other suitable means and immediately below the latch strip 44 and engaging the lower surface of the elongated portion 42 of the arm 35 is a strap 45 of resilient material which is secured at its ends 46 and 47 to the tray 14). The resiliency of the strap 45 serves to urge the offset portion 42 of the arm 35 upwardly into engagement with the latch strip 44 or into engagement with the lower surface of the tray 18 depending upon the position of the offset portion 42.

A cam plate 48 is pivotally mounted by a rivet 49 or other suitable means on the portion 43 extending at right angles to the offset portion 42 of the arm 35 and the cam plate 48 is provided with an arcuate slot 50 which serves to receive a pin 51 projecting from the surface of the angular portion 43. Pin 51 serves as a stop to limit pivotal movement of the cam plate 48 on the pivot pin 49 in a manner to be presently described. A roller 52 is rotatably mounted on a pin 53 extending from the cam plate 48 adjacent one edge thereof and adjacent the opposite edge of the cam plate 48 an actuating handle 54 extends outwardly beyond the edge of the tray 10 to permit convenient operation of the cam plate 48 by the hand of the operator.

If desired, the lower surface of the tray 10 may be provided with a wear plate 55 for engagement by the roller 52, but such wear plate is only necessary where the material from which the tray 10 is made is relatively soft and in the event this is relatively hard material, no wear plate is necessary. In the case of a wood tray or table however, a wear plate might possibly assist in operation of the device, since friction would tend to be reduced thereby.

As mentioned above, the legs 11 and 12 may be extended or retracted by oscillation of the arm 35 and this is normally accomplished by movement of the handle 54 in either direction as the case may be. As shown in Fig. 1, the legs 11 and 12 are in extended position and the offset portion 42 of the arm 35 engages the end 56 of latch strip 44 and is held in such position by the resiliency of the strap 45 engaging the lower surface of the offset portion 42. Also in this position, as best shown in Fig. 5, the offset portion 42 engages the lower surface of the tray 10. In this position it is to be noted, that the pin 51 is located near one end of the arcuate slot 50 in the cam plate 48 and when it is desired to retract the legs 11 and 12, the handle 54 is moved toward the left, as viewed in Fig. l, which serves to rotate the cam plate 48 about the pivot pin 49 and move the roller 52 into engagement with the wear plate 55 which acts as a cam and tends to move the offset portion 52 of the arm 35 away from the lower surface of tray 10 and below the lower surface of latch strip 44, at which time the offset portion 42 may move toward the left, as viewed in Fig. l, to rotate the shafts 19 and 29, thus moving the legs 11 and 12 toward retracted position. During this movement of the arm 35, the cam plate 48 moves over dead center to the position shown in dotted lines at the left of Fig. 6, and when the offset portion 42 of the arm 35 reaches the end 57 of the latch strip 44, the resilient strap 45 urges the offset portion 42 upwardly into engagement with the lower surface of the tray 10 and the end 57 of the latch strip 44 which serves to securely latch the legs 11 and 12 in retracted position.

Movement of the handle 54 toward the right, as viewed in Fig. 1, serves to release the offset portion 42 from the end 57 of the latch strip 44 and permits movement of the arm 35 toward the right to extend the legs 11 and 12 and during this movement, the cam plate 48 moves over dead center to the position shown in Fig. 3, and upon engagement of the oifset portion 42 with the end 56 of latch strip 44, the legs 11 and 12 are securely locked in extended position.

It will be seen that by the above described invention there has been provided a relatively simple and convenient means for extending and retracting legs or other supporting means which may be applied to a tray or table or other supporting surface, which means is conveniently, operated by a single actuating handle and which means likewise, serves to securely lock the legs or supporting means in extended or retracted position. The mechanism of this invention may, of course, be applied as well to single legs as to the legs of the type illustrated, and it is to be noted that all of the parts may be conveniently manufactured by die stamping or equivalent operations, thus maintaining cost of manufacture at a minimum.

It will be obvious to those skilled in the art that various changes may be made in the invention without departing from the spirit and scope thereof and therefore, the invention is not limited by that which is shown in the drawing and described in the specification, but only as indicated in the appended claims.

What is claimed is:

l. Retractable and extendable supporting means comprising legs pivotally mounted on a member to be supported, an operating arm pivotally mounted on said member, links connecting said arm and said legs, an upwardly offset portion in said arm, latch means secured to said member in the path of movement of said offset portion, a resilient strap secured to said member and engaging said arm to urge the same upwardly toward the lower surface of said member, whereby said offset portion may engage said latch means to lock said legs in retracted or extended position, a cam plate pivotally mounted on said arm, a roller mounted on said cam plate, and a handle on said cam plate whereby upon .selective movement of said handle and cam plate in either direction said roller will engage the lower surface of said member to disengage said offset portion from said latch means to permit movement of said arm by said handle to actuate said links and move said legs to retracted or extended position.

2. Retractable and extendable supporting means comprising legs pivotally mounted on a member to be supported, an operating arm pivotally mounted on said member, links connecting said arm and said legs, an upwardly offset portion in said arm terminating in a downwardly extending portion, a latch strip secured to the lower sur face of said member in the path of movement of said offset portion, a resilient strap secured to said member and engaging said arm to urge the same upwardly toward the lower surface of said member, whereby said offset portion may selectively engage either end of said latch strip to lock said legs in retracted or extended position, a cam plate pivotally mounted on said downwardly extending portion, a roller mounted on said cam plate, and a handle on said cam plate whereby upon selective movement of said handle and cam plate in either direction said roller will engage the lower surface of said member to disengage said offset portion from the end of said latch strip to permit movement of said arm by said handle to actuate said links and move said legs to retracted or extended position.

3. Retractable and extendable supporting means comprising legs pivotally mounted on a member to be supported adjacent opposite edges thereof, an operating arm pivotally mounted on said member, links connecting said arm and said legs, an upwardly offset portion in said arm terminating in a downwardly extending portion, a latch strip secured to the lower surface of said member in the path of movement of said offset portion, a resilient strap secured to said member and engaging said arm to urge the same upwardly toward the lower surface of said member, whereby said offset portion may selectively engage either end of said latch strip to lock said legs in retracted or extended position, a cam plate pivotally mounted on said downwardly extending portion, stop means for limiting pivotal movement of said cam plate, a roller mounted on said cam plate and a handle on said cam plate whereby upon selective movement of said handle and cam plate in either direction said roller will engage the lower surface of said member to disengage said offset portion from the end of said latch strip to permit movement of said arm by said handle to actuate said links and move said legs to retracted or extended position.

4. Retractable and extendable supporting means comprising a pair of generally U-shaped legs pivotally mounted on a member to be supported adjacent opposite edges thereof, an operating arm pivotally mounted on said member and extending substantially parallel to the lower surface of said member, links connecting said arm and said legs, anupwardly offset portion in said arm terminating in a downwardly extending portion, a latch strip secured to the lower surface of said member in the path of movement of said offset portion, a resilient strap secured to said member and engaging said arm to urge the same upwardly toward the lower surface of said member, whereby said offset portion may selectively engage either end of said latch strip to lock said legs in retracted or extended position, a cam plate pivotally mounted on said downwardly extending portion, stop means for limiting pivotal movement of said cam plate, a roller mounted on said cam plate and a handle on said cam plate whereby upon selective movement of said handle and cam plate in either direction said roller will engage the lower surface of said member to disengage said offset portion from the end of said latch strip to permit movement of said arm by said handle to actuate said links and move said legs to retracted or extended position.

5; Retractable and extendable supporting means comprising a pair of generally U-shaped legs pivotally mounted on a member to be supported adjacent opposite edges thereof, an operating arm pivotally mounted on said member and extending substantially parallel to the lower surface of said member, links connecting said arm and said legs, an upwardly offset portion in said arm terminating in a downwardly extending portion, a latch strip secured to the lower surface of said member in the path of movement of said offset portion, a resilient strap secured to said member and engaging said arm to urge the same upwardly toward the lower surface of said member, whereby said offset portion may selectively engage either end of said latch strip to lock said legs in retracted or extended position, a cam plate pivotally mounted on said downwardly extending portion, stop means for limiting pivotal movement of said cam plate, a roller mounted on said cam plate, a wear plate on the lower surface of said member for engagement by said roller and a handle on said cam plate whereby upon selective movement of said handle and cam plate in either direction said roller will engage said wear plate to disengage said offset portion from the end of said latch strip to permit movement of said arm by said handle to actuate said links and move said legs to retracted or extended position.

References Cited in the file of this patent UNITED STATES PATENTS 1,534,470 Smith Apr. 21, 1925 2,213,681 Symmonds Sept. 3, 1940 2,490,318 Padon Dec. 6, 1949 2,533,173 Mitchell Dec. 5, 1950 2,574,281 Olson Nov. 6, 1951 

